package com.app.shop.util.weixin;

import java.io.UnsupportedEncodingException;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.security.spec.InvalidParameterSpecException;
import java.util.Arrays;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.log4j.Logger;



import com.alibaba.fastjson.util.Base64;

/**
 * @Title
 * @Description (微信Util)
 * @author Garfield Miao
 * @date 2019年21月27日
 * @upAuthor Garfield Miao
 * @update 2019年21月27日
 */
public class ASEUtil {
	 private static final Logger LOG = Logger.getLogger(ASEUtil.class);
	
	public static String getUserInfo(String encryptedData, String sessionkey,
			String iv) { 
		// 被加密的数据 byte[]
		byte[] dataByte = Base64.decodeFast(encryptedData);
		// 加密秘钥
		byte[] keyByte = Base64.decodeFast(sessionkey);
		// 偏移量
		byte[] ivByte = Base64.decodeFast(iv);
		try {
			// 如果密钥不足16位，那么就补足. 这个if 中的内容很重要
			int base = 16;
			if (keyByte.length % base != 0) {
				int groups = keyByte.length / base
						+ (keyByte.length % base != 0 ? 1 : 0);
				byte[] temp = new byte[groups * base];
				Arrays.fill(temp, (byte) 0);
				System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
				keyByte = temp;
			}
			// 初始化
			Security.addProvider(new BouncyCastleProvider());
			Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", "BC");
			SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
			AlgorithmParameters parameters = AlgorithmParameters
					.getInstance("AES");
			parameters.init(new IvParameterSpec(ivByte));
			cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
			// 初始化
			byte[] resultByte = cipher.doFinal(dataByte);
			if (null != resultByte && resultByte.length > 0) {
				String result = new String(resultByte, "UTF-8");
				return result;
			}
		} catch (NoSuchAlgorithmException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (NoSuchPaddingException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (InvalidParameterSpecException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (IllegalBlockSizeException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (BadPaddingException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (UnsupportedEncodingException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (InvalidKeyException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (InvalidAlgorithmParameterException e) {
			//e.printStackTrace();
			LOG.error(e);
		} catch (NoSuchProviderException e) {
			//e.printStackTrace();
			LOG.error(e);
		}
		return null;
	}
	
}
